CARB CLEANING
I read with interest the comments in the magazine concerning the cleaning (or not) of carburettors in an ultrasonic bath. For me it’s a no brainer. Once the carbs are off the bike they go straight in the bath. If I have old solution in there I will drop the carbs in before stripping them. Let them cook at 60°C for half an hour. Then drain the bath, clean it, replenish the solution and start stripping the carbs. They come apart easier once saturated with heat. When I strip the carbs I use plastic tubs to keep each carb’s components separate. I also use these in the bath to save losing bits at the bottom. You can just put water in the bath and diluted solution in the tubs.
Once thoroughly clean, I reassemble and check / change the jets, worn parts, O-rings and diaphragms as required. Once the float level has been checked and reset I check the float heights again using a remote tank at 4ft head to check the needle valves. If the float bowl gaskets have swollen and doubled in size due to not being E5/10 resistant, boiling them in a kettle for two minutes will return them to their original size. Doing it this way saves chasing missed issues later.
I know of one person last week who refitted his bank of four carbs three times (a right pita) without properly stripping them, ignoring my advice… only to find he had two split / perished diaphragms and leaking needles. No wonder it flooded and wouldn’t pull past 5000rpm.
I have two baths, both heated. One is a generic bench-top 7L Chinese Amazon £200 stainless unit that uses integral piezo pads and drivers. The other is a 50L flush bench mounted unit that uses 8 x 4 inch toroidal windings and an external driver unit.
In both I use an ultrasonic carburettor cleaner from Allendale Electronics (also from Amazon). I buy it in 5L containers for around £20 a time and it’s diluted 10:1 with filtered water.
It’s important not to use any cleaner with a flash point (like fuel, paraffin, carb cleaner) as it can be ignited by the high frequency vibration. Water-based cleaners are all that is necessary as it’s the bubbles generated by the high frequency vibration that do most of the work. I filter and reuse the fluid a couple of times as it can become expensive if you have to keep changing it. Especially in the 50L bath as that takes 4.5 litres of fluid at a time.
One of the photos shows the carbs from a Thunderbird Sport, rebuilt using kits from Total Triumph. The bodies were separated for their final clean and fuel O-rings replaced with Vitriol items.
Richard Stiles, member
I’m always amazed at the amount of crap the ultrasonic cleaner gets out of the carbs. This was a fresh solution at the start of the day. I cleaned three monoblocs that didn’t look that dirty to begin to with. To anyone debating getting one, I say do it, they are well worth the money.
Tom Watson, member
I’ve been looking for an ultrasonic cleaner for a while, and finally settled on the Allendale six-litre Carb Kit digital version, with a degassing function and selection of settings. It comes with a basket and carb solution. The size nicely fits one R90S Dell’ Orto carb... so it was time to switch it on and start decrudding!
Photos show the carb before and after. The components fit well in the bath. Given the need for space around them during the cycles, it doesn’t do to pack too much in.
Talana Gamah, member